Modular three-dimensional optical switch

• US 6,567,574 B1
• Filed: 10/06/2000
• Issued: 05/20/2003
• Est. Priority Date: 10/06/2000
• Status: Expired due to Fees

• Current Assignee: Crossfiber Inc., Omx Incorporated (Office Depot LLC)
• Original Assignee: Omx Incorporated (Office Depot LLC)
• Inventors: Ma, Jian, Kruglick, Ezekiel John Joseph, Reiley, Daniel J., Gloeckner, Steffen, Marchand, Philippe Jean
• Primary Examiner(s): Kim, Ellen E.
• Application Number:
  US09/680,648
• Time in Patent Office: 956 Days
• Field of Search: 385/16-20
• US Class Current: 385/16
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/359 of the position of the moving element itself during switching, i.e. without monitoring the switched beams
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0043 Fault tolerance
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

A modular three-dimensional (3D) optical switch that is scalable and that provides monitor and control of MEMS mirror arrays. A first switch module includes an array of input channels. Light beams received from the input channels are directed toward a first wavelength selective mirror. The light beams are reflected off of the first wavelength selective mirror and onto a first array of moveable micromirrors. The moveable micromirrors are adjusted so that the light beams reflect therefrom and enter a second switch module where they impinge upon a second array of moveable micromirrors. The light beams reflect off of the second array of moveable micromirrors and impinge upon a second wavelength selective mirror. The light beams reflect off of the second wavelength selective mirror and into an array of output channels. The alignment or misalignment of a data path through the switch is detected by directing two monitor beams through the data path, one in the forward direction and one in the reverse direction. The position of each of the monitor beams is detected after its reflection from the second moveable micromirror that it hits. The position data is used to determine the angles of the moveable micromirrors in the data path.

Claims

1. A method of detecting alignment of an optical path through an optical switch, comprising the steps of:

directing a first monitor beam in a forward direction along at least a portion of the optical path, the at least a portion of the optical path including reflection off of a first moveable optical redirecting device and a second moveable optical redirecting device;

detecting a position of the first monitor beam that is reflected off of the second moveable optical redirecting device;

directing a second monitor beam in a reverse direction along the at least a portion of the optical path; and

detecting a position of the second monitor beam that is reflected off of the first moveable optical redirecting device.

2. A method in accordance with claim 1, further comprising the step of:

determining a magnitude of at least one angle associated with at least one of the first and second moveable optical redirecting devices based on the detected positions of the first and second monitor beams.

3. A method in accordance with claim 2, wherein the determination of the magnitude of at least one angle is further based on a first distance between the first and second moveable optical redirecting devices, a second distance between the second moveable optical redirecting device and a detector for detecting the position of the first monitor beam, and a third distance between the first moveable optical redirecting device and a detector for detecting the position of the second monitor beam.

4. A method in accordance with claim 1, wherein each of the first and second moveable optical redirecting devices comprises a moveable optical redirecting device that is moveable in two dimensions.

5. A method in accordance with claim 1, wherein each step of detecting further comprises the step of:

detecting a position with a planar array of detectors.

6. A method in accordance with claim 1, further comprising the step of:

transmitting at least a portion of the first monitor beam that is reflected off of the second moveable optical redirecting device through a first wavelength selective optical redirecting device.

7. A method in accordance with claim 6, further comprising the step of:

transmitting at least a portion of the second monitor beam that is reflected off of the first moveable optical redirecting device through a second wavelength selective optical redirecting device.

8. A method in accordance with claim 1, wherein the optical path comprises:

a path followed by a light beam as it exits an optical input channel, reflects off of a first wavelength selective optical redirecting device, reflects off of the first moveable optical redirecting device, reflects off of the second moveable optical redirecting device, reflects off of a second wavelength selective optical redirecting device, and enters an optical output channel.

9. A method in accordance with claim 8, wherein the step of directing a first monitor beam in a forward direction along at least a portion of the optical path comprises the step of:

tapping the first monitor beam into the optical input channel.

10. A method in accordance with claim 8, wherein the step of directing a first monitor beam in a forward direction along at least a portion of the optical path comprises the step of:

transmitting at least a portion of the first monitor beam through the first wavelength selective optical redirecting device in a direction towards the first moveable optical redirecting device.

11. A method in accordance with claim 10, wherein the step of directing a first monitor beam in a forward direction along at least a portion of the optical path further comprises the step of:

directing the first monitor beam to the first wavelength selective optical redirecting device with a beam splitter.

12. A method in accordance with claim 10, wherein the step of directing a first monitor beam in a forward direction along at least a portion of the optical path further comprises the steps of:

providing a detector capable of receiving the first monitoring signal transmitted through the second wavelength selective optical redirecting device;

transmitting at least a portion of the first monitoring beam through the second wavelength selective optical redirecting device such that the transmitted portion of the first monitoring beam impinges upon the detector array.

13. A method in accordance with claim 8, wherein the step of directing a second monitor beam in a reverse direction along the at least a portion of the optical path comprises the step of:

tapping the second monitor beam into the optical output channel.

14. A method in accordance with claim 8, wherein the step of directing a second monitor beam in a reverse direction along the at least a portion of the optical path comprises the step of:

transmitting at least a portion of the second monitor beam through the second wavelength selective optical redirecting device in a direction towards the second moveable optical redirecting device.

15. A method in accordance with claim 14, wherein the step of directing a second monitor beam in a reverse direction along the at least a portion of the optical path further comprises the step of:

directing the second monitor beam to the second wavelength selective optical redirecting device with a beam splitter.

16. A method in accordance with claim 1, wherein the step of directing a second monitor beam in a reverse direction along the at least a portion of the optical path comprises the step of:

at least partially reflecting the first monitor beam directly backwards to form the second monitor beam.

17. A method in accordance with claim 16, wherein the step of at least partially reflecting the first monitor beam directly backwards to form the second monitor beam comprises the step of:

at least partially reflecting the first monitor beam directly backwards with a beam splitter positioned in front of a detector used to detect the position of the first monitor beam.

18. A method of switching an optical input channel to an optical output channel, comprising the steps of:

directing a light beam that originates from the optical input channel toward a first moveable optical redirecting device;

reflecting the light beam off of the first moveable optical redirecting device and onto a second moveable optical redirecting device;

reflecting the light beam off of the second moveable optical redirecting device;

directing the light beam reflected off of the second moveable optical redirecting device into the optical output channel; and

directing a first monitor beam along at least a portion of a same path traveled by the light beam.

19. A method in accordance with claim 18, further comprising the step of:

detecting a position of the first monitor beam after it is reflected off of the second moveable optical redirecting device.

20. A method in accordance with claim 18, further comprising the step of:

directing a second monitor beam along the at least a portion of the same path traveled by the light beam in a reverse direction.

21. A method in accordance with claim 20, further comprising the step of:

detecting a position of the second monitor beam after it is reflected off of the first moveable optical redirecting device.

22. A method in accordance with claim 18, wherein the each of the first and second moveable optical redirecting devices comprises a moveable optical redirecting device that is moveable in two dimensions.

23. A method in accordance with claim 18, wherein the step of directing the light beam reflected off of the second moveable optical redirecting device into the optical output channel comprises the step of:

reflecting the light beam off of a first wavelength selective optical redirecting device and into the optical output channel.

24. A method in accordance with claim 23, further comprising the step of:

transmitting at least a portion of the first monitor beam through the first wavelength selective optical redirecting device.

25. A method in accordance with claim 23, wherein the step of directing a first monitor beam along at least a portion of the same path traveled by the light beam further comprises the steps of:

providing a detector capable of receiving the first monitoring signal transmitted through the second wavelength selective optical redirecting device;

transmitting at least a portion of the first monitoring beam through the second wavelength selective optical redirecting device such that the transmitted portion of the first monitoring beam impinges upon the detector array.

26. A method in accordance with claim 18, wherein the step of directing a light beam that originates from the optical input channel toward a first moveable optical redirecting device comprises the step of:

reflecting the light beam off of a first wavelength selective optical redirecting device and onto the first moveable optical redirecting device.

27. A method in accordance with claim 26, further comprising the steps of:

directing a second monitor beam along the at least a portion of the same path traveled by the light beam in a reverse direction; and

transmitting at least a portion of the second monitor beam through the first wavelength selective optical redirecting device.

28. A method in accordance with claim 18, further comprising the step of:

at least partially reflecting the first monitor beam directly backwards so that the partially reflected first monitor beam travels in a reverse direction along the at least a portion of the same path traveled by the light beam.

29. A method in accordance with claim 28, wherein the step of at least partially reflecting the first monitor beam directly backwards comprises the step of:

at least partially reflecting the first monitor beam directly backwards with a beam splitter positioned in front of a detector used to detect the position of the first monitor beam.

30. A method of switching an optical input channel to an optical output channel, comprising the steps of:

directing a light beam received from the optical input channel toward a first wavelength selective optical redirecting device;

reflecting the light beam off of the first wavelength selective optical redirecting device and onto a first moveable optical redirecting device;

adjusting the first moveable optical redirecting device so that the light beam reflects therefrom and impinges upon a second moveable optical redirecting device;

adjusting the second moveable optical redirecting device so that the light beam reflects therefrom and impinges upon a second wavelength selective optical redirecting device; and

reflecting a first portion of the light beam off of the second wavelength selective optical redirecting device and into the optical output channel and coupling a second portion of the light beam to a detector via the second wavelength selective optical redirecting device.

31. A method in accordance with claim 30, further comprising the step of:

directing a first monitor beam along a same path traveled by the light beam between the first wavelength selective optical redirecting device and the second wavelength selective optical redirecting device.

32. A method in accordance with claim 31, further comprising the step of:

transmitting at least a portion of the first monitor beam through the second wavelength selective optical redirecting device.

33. A method in accordance with claim 32, further comprising the step of:

detecting a position of the transmitted portion of the first monitor beam.

34. A method in accordance with claim 33, wherein the step of detecting further comprises the step of:

detecting a position of the transmitted portion of the first monitor beam with a planar array of detectors that is positioned substantially parallel to the optical output channel.

35. A method in accordance with claim 31, further comprising the step of:

directing a second monitor beam along the same path in a reverse direction.

36. A method in accordance with claim 35, further comprising the step of:

transmitting at least a portion of the second monitor beam through the first wavelength selective optical redirecting device.

37. A method in accordance with claim 36, further comprising the step of:

detecting a position of the transmitted portion of the second monitor beam.

38. A method in accordance with claim 30, wherein the each of the first and second moveable optical redirecting devices comprises a moveable optical redirecting device that is moveable in two dimensions.

39. A method in accordance with claim 30, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices with the first moveable optical redirecting device corresponding to the optical input channel.

40. A method in accordance with claim 30, wherein the second moveable optical redirecting device is embodied in a second array of moveable optical redirecting devices with the second moveable optical redirecting device corresponding to the optical output channel.

41. A method in accordance with claim 30, wherein the first wavelength selective optical redirecting device is positioned to form an approximately forty-five degree angle with the optical input channel, and the second wavelength selective optical redirecting device is positioned to form an approximately forty-five degree angle with the optical output channel.

42. A method in accordance with claim 41, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices that is substantially parallel to the first wavelength selective optical redirecting device, and the second moveable optical redirecting device is embodied in a second array of moveable optical redirecting devices that is substantially parallel to the second wavelength selective optical redirecting device.

43. A method in accordance with claim 30, wherein the optical input channel is embodied in an array of optical input channels, and the optical output channel is embodied in an array of optical output channels.

44. An apparatus for use in optical switching, comprising:

a first switch module that includes

an optical input channel,

a first moveable optical redirecting device, and

a first wavelength selective optical redirecting device positioned to reflect a light beam received from the optical input channel onto the first moveable optical redirecting device, and

a first detector capable of receiving at least a portion of a light beam passing through the first wavelength selective optical redirecting device; and

a second switch module that includes an optical output channel, a second moveable optical redirecting device, and a second wavelength selective optical redirecting device positioned to reflect the light beam received from the second moveable optical redirecting device into the optical output channel;

wherein the first switch module and the second switch module are positioned so that the light beam can be reflected from the first moveable optical redirecting device and impinge upon the second moveable optical redirecting device.

45. An apparatus in accordance with claim 44, further comprising:

means for directing a first monitor beam along a same path traveled by the light beam that includes reflection off of the first moveable optical redirecting device and the second moveable optical redirecting device.

46. An apparatus in accordance with claim 45, wherein the second wavelength selective optical redirecting device comprises optical properties such that at least a portion of the first monitor beam is transmitted therethrough.

47. An apparatus in accordance with claim 46, further comprising:

a first detector configured to detect a position of the transmitted portion of the first monitor beam.

48. An apparatus in accordance with claim 45, further comprising:

means for directing a second monitor beam along the same path in a reverse direction.

49. An apparatus in accordance with claim 48, wherein the first wavelength selective optical redirecting device comprises optical properties such that at least a portion of the second monitor beam is transmitted therethrough.

50. An apparatus in accordance with claim 49, further comprising:

a second detector configured to detect a position of the transmitted portion of the second monitor beam.

51. An apparatus in accordance with claim 45, wherein the means for directing a first monitor beam comprises:

a wavelength selective device for tapping the first monitor beam into the optical input channel.

52. An apparatus in accordance with claim 45, wherein the means for directing a first monitor beam comprises:

a beam splitter configured to direct the first monitor beam toward the first wavelength selective optical redirecting device so that at least a portion of the first monitoring beam is transmitted therethrough.

53. An apparatus in accordance with claim 45, wherein the second switch module further comprises:

means for at least partially reflecting the first monitor beam directly backwards so that the partially reflected first monitor beam travels in a reverse direction along the same path.

54. An apparatus in accordance with claim 53, wherein the means for at least partially reflecting the first monitor beam directly backwards comprises:

a beam splitter positioned in front of a detector used to detect a position of the first monitor beam.

55. An apparatus in accordance with claim 44, wherein each of the first and second moveable optical redirecting devices comprises a moveable optical redirecting device that is moveable in two dimensions.

56. An apparatus in accordance with claim 44, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices with the first moveable optical redirecting device corresponding to the optical input channel.

57. An apparatus in accordance with claim 44, wherein the second moveable optical redirecting device is embodied in a second array of moveable optical redirecting devices with the second moveable optical redirecting device corresponding to the optical output channel.

58. An apparatus in accordance with claim 44, wherein the first wavelength selective optical redirecting device is positioned to form an approximately forty-five degree angle with the optical input channel, and the second wavelength selective optical redirecting device is positioned to form an approximately forty-five degree angle with the optical output channel.

59. An apparatus in accordance with claim 58, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices that is substantially parallel to the first wavelength selective optical redirecting device, and the second moveable optical redirecting device is embodied in a second array of moveable optical redirecting devices that is substantially parallel to the second wavelength selective optical redirecting device.

60. An apparatus in accordance with claim 44, wherein the optical input channel is embodied in an array of optical input channels, and the optical output channel is embodied in an array of optical output channels.

61. An apparatus for use in optical switching, comprising:

a first switch module that includes,

an optical input channel;

a first moveable optical redirecting device;

a first wavelength selective optical redirecting device positioned to reflect a light beam received from the optical input channel onto the first moveable optical redirecting device; and

a detector configured to detect a position of a first monitor beam that is reflected off of the first moveable optical redirecting device and that at least a portion of which is transmitted through the first wavelength selective optical redirecting device.

62. An apparatus in accordance with claim 61, further comprising:

means for directing a second monitor beam along a same path traveled by the first monitor beam and in an opposite direction.

63. An apparatus in accordance with claim 62, wherein the means for directing a second monitor beam comprises:

a tap configured to tap the second monitor beam into the optical input channel.

64. An apparatus in accordance with claim 62, wherein the means for directing a first monitor beam comprises:

a beam splitter configured to direct the second monitor beam toward the first wavelength selective optical redirecting device so that at least a portion of the second monitoring beam is transmitted therethrough.

65. An apparatus in accordance with claim 64, further comprising a detector positioned to receive at least a portion of the second monitoring beam that is transmitted through the first wavelength selective optical redirecting device.

66. An apparatus in accordance with claim 61, wherein the first moveable optical redirecting device comprises a moveable optical redirecting device that is moveable in two dimensions.

67. An apparatus in accordance with claim 61, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices with the first moveable optical redirecting device corresponding to the optical input channel.

68. An apparatus in accordance with claim 61, wherein the first wavelength selective optical redirecting device is positioned to form an approximately forty-five degree angle with the optical input channel.

69. An apparatus in accordance with claim 68, wherein the first moveable optical redirecting device is embodied in a first array of moveable optical redirecting devices that is substantially parallel to the first wavelength selective optical redirecting device.

70. An apparatus in accordance with claim 61, wherein the optical input channel is embodied in an array of optical input channels.

71. An apparatus in accordance with claim 61, further comprising:

a second switch module that includes an optical output channel, a second moveable optical redirecting device, and a second wavelength selective optical redirecting device positioned to reflect the light beam received from the second moveable optical redirecting device into the optical output channel;

wherein the first switch module and the second switch module are positioned so that the light beam can be reflected from the first moveable optical redirecting device and impinge upon the second moveable optical redirecting device.